一种小功率孔形阳极喷嘴等离子体炬的研究

Low-Power Plasma Torch with Hole-Mouthed Anode

关键词:  等离子体炬  点火  数值计算  光谱  孔形阳极

Key words:  Plasma torch  Ignition  Numerical calculation  Spectrogram  Hole-mouthed anode

摘要:

为了提高小功率等离子体炬的综合性能，研制了一种新型具有孔形阳极喷嘴的小功率等离子体炬，功率1~5kW。采用流体模拟计算的方法，计算了喷嘴出口附近射流的流场结构特点。通过实验分别测试了采用氩气、氮气作为工质气体时等离子体炬的运行电流和电压，观察了等离子体射流形态和电极烧蚀情况，通过测量等离子体射流前方中心轴线位置处的光谱的方法计算射流温度，采用气体分析仪测量了等离子体射流附近的二氧化氮浓度。测得的试验数据显示相同工质流率和电流条件下，氮气等离子体射流运行电压远高于氩气，而光谱测得氩气射流的温度远高于氮气。氮气等离子体射流和外界空气接触产生了少量的副产物二氧化氮（低于10mL/m³），而氩气等离子体射流附近无二氧化氮产生。

Abstract:

In order to upgrade the performance of the low-power plasma torch， a new-type low-power plasma torch with hole-mouthed anode was developed with the power of the plasma torch being 1~5kW. Research of thermal flow field close-by anode nozzle of plasma jet is done through the numerical simulation. The voltage and current were measured with gas-flow components such as argon and nitrogen， the form of plasma jet and ablation of electrodes were observed， temperature of plasma jet was measured by spectral analysis with fiber optical probe of spectrograph on the axis right in front of plasma jet， concentration value of NO₂ near plasma jet was measured by gas analyzer. With the same flowrate of feedstock and electric current， the voltage of plasma jet of nitrogen exceeds that of argon， but the temperature of plasma jet measured by spectrometer with argon exceeds that of nitrogen. Gaseous by-products such as NO₂ which generated from nitrogen-plasma jet and surrounding air was measured by with concentration below 10mL/m³， but no NO₂ was measured from argon-plasma jet.